At pH = X, \(\text{CrO}_4^{2-}\)​ (yellow) changes to \(\text{Cr}_2\text{O}_7^{2-}\) (orange), and vice versa at pH = Y.
What are the values of X and Y, respectively?

1. 6, and 8

2. 6, and 5

3. 8, and 6

4. 7, and 7

The colour of KMnO₄ is due to  :

1. d-d transition

2. Charge transfer spectra

3. Polarisation of ion

4. p-d transition

Cr₂O₇^2-+X$\stackrel{{\mathrm{H}}^{+}}{\to }$Cr³⁺+H₂O + oxidized product of X. X in the above reaction cannot be

1. C₂O₄^2-

2. Fe²⁺

3. SO₄^2-

4. S^2-

In the dichromate ion Cr₂O₇^2-,

1. 4 Cr-O bonds are equivalent

2. 6 Cr-O bonds are equivalent

3. All Cr-O bonds are equivalent

4. None of Cr-O bonds are equivalent

Name the gas that can readily decolourise acidified KMnO₄ solution.

(1) CO₂           

(2) SO₂           

(3) NO₂             

(4) P₂O₅

HgCl₂ and I₂ both when dissolved in water containing I^- ions the pair of species formed is

(a) HgI₂, ${\mathrm{I}}_3^{-}$                              (b) HgI₂, I^-

(c) ${\mathrm{HgI}}_4^{2-},<mspace\; width="1em"></mspace>{\mathrm{I}}_3^{-}$                             (d) Hg₂I₂, I^-

Which one of the following statements is correct when SO₂ is passed through acidified

K₂Cr₂O₇ solution?

1. The solution is decolourized

2. SO₂ is reduced

3. Green Cr₂(SO₄)₃ is formed

4. The solution turns blue

Which of the statements is not true?

1. On passing H₂S through acidified K₂Cr₂O₇ solution, a milky colour is observed

2. Na₂Cr₂O₇ is preferred over K₂Cr₂O₇ in volumteric analysis

3. K₂Cr₂O₇ solution in acidic medium is orange

4. K₂Cr₂O₇ solution becomes yellow on increasing the pH beyond 7

Acidified permanganate solution does not oxidize:

(1) ${\mathrm{C}}_2{\mathrm{O}}_4^{2-}\left(\mathrm{aq}\right)$                   

(2) ${\mathrm{NO}}_2^{-}\left(\mathrm{aq}\right)$

(3) ${\mathrm{S}}^{2-}\left(\mathrm{aq}\right)$                         

(4) ${\mathrm{F}}^{-}\left(\mathrm{aq}\right)$

At $300°\mathrm{C},<mspace\; width="1em"></mspace>{\mathrm{FeCl}}_3<mspace\; width="1em"></mspace>:$

1. Decomposes into ${\mathrm{FeCl}}_2<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{Cl}}_2.$               

2. Decomposes into $\mathrm{Fe}<mspace\; width="1em"></mspace>\mathrm{and}<mspace\; width="1em"></mspace>{\mathrm{Cl}}_2.$

3. Sublimes go give liquid ${\mathrm{FeCl}}_3$                         

4. Sublimes to give gaseous dimmer ${\left({\mathrm{FeCl}}_3\right)}_2.$